Such bowling game systems are configured with: an approach where players roll a ball; a lane extending from the approach and on which the ball rolls; a group of pins placed on the end of the lane opposite the approach; and trough-like gutters lying on either side of the lane and receiving balls slipping off the lane. Players enjoy the game by competing with each other for a higher score that depends on the number of pins they knock down.
Of course, how many pins players are able to knock down depends on the direction in which the ball is rolled—that is, players' scores are determined by which part of the arranged pins their balls strike, and on the players' skill at controlling the ball.
Being not yet fully developed physically, children are not able to control very well the direction in which the ball rolls, and consequently cannot hope for a high score, or as is likely to happen, they are able to knock down only a few pins because the ball always falls into the gutter. In such cases, children lose interest in the bowling game, and are left unable to enjoy household bowling outings with the object of interacting as a family.
In light of such considerations, various gutter-ball prevention apparatuses for preventing a bowled ball from falling into the gutter have been proposed to date. One such apparatus is configured so that bars, which are placed along both sides of the lane, simultaneously shift horizontally between a blocking position near the edge of the lane, where the bars prevent the ball from falling into the gutter, and a retract position near the edge of the gutters, where the bars shift from the blocking position. (Reference is made to Japanese Unexamined Pat. App. Pub. Nos. H7-155424, No. H9-84923 and No. H11-164931.)
In accordance with this gutter prevention apparatus, the bars shift into the blocking position when players, such as young children, unable to control a ball well bowl, and shift into the retract position when physically more developed adolescent players bowl.
Thus, even if a ball rolled by a juvenile player unable to control the direction of the rolling ball well rolls toward a gutter, the bars shift into the blocking position to prevent the ball from falling into the gutter keeping it on the lane, such that the ball runs into the pins and knocks down some of them as a result. In other words, even children are able to always knock down some of the pins and score.
The bars are shifted into the retract position when non-children players bowl, so that any gutter balls they bowl will fall directly into the gutter without being blocked.
The fact that this gutter prevention apparatus allows children to always knock down some of the pins and score encourages them to maintain interest in the game. Moreover, children are able to bowl along with adolescent and older players in the same lane, so that they are able to enjoy a household bowling outing and interact as a family.
Additionally, the following apparatuses have been also proposed: an apparatus configured so that bars simultaneously shift vertically between a blocking position and a retract position lower than the blocking position (cf. Japanese Unexamined Pat. App. Pub. Nos. H10-151235 and 2002-65933), and an apparatus configured so that the gutters rotate toward the lane about axes paralleling the lane lengthwise (cf. Japanese Unexamined Pat. App. Pub. No. H10-506031). Both of these apparatuses play the same role as that of the apparatus explained in the foregoing.    Patent Document 1: Japanese Unexamined Pat. App. Pub. No. H7-155424.    Patent Document 2: Japanese Unexamined Pat. App. Pub. No. H9-84923.    Patent Document 2: Japanese Unexamined Pat. App. Pub. No. H11-164931.    Patent Document 2: Japanese Unexamined Pat. App. Pub. No. H10-151235.    Patent Document 2: Japanese Unexamined Pat. App. Pub. No. 2002-65933.    Patent Document 2: Japanese Unexamined Pat. App. Pub. No. H10-506031.